The present invention relates to apparatus for continuously mixing an aggregation of wet and dry materials and a gas to produce a product of predetermined density. More particularly, it relates to mixing apparatus of this character in which the density of the mixed product is sensed and utilized to control the flow of gas to the apparatus automatically in such fashion as to maintain the density of the mixed product substantially uniform.
In the baking industry, bakery products are produced continuously by premixing certain dry and wet ingredients, and subjecting the premix to vigorous mixing in the presence of a gas, usually air, in a continuous mixer. If a final product of uniform good quality is to be achieved at minimum cost it is essential that the density of the product mix be maintained substantially constant at all times. This requires that the bakery operator take samples of the mix from time to time, weight them to ascertain the density of the mix, and manually adjust the amount of air introduced into the mix as required to maintain the product density constant. Because of the inconvenience that this entails, it is often the practice to adjust the air supply and other ingredients to achieve the desired product density only at the beginning of a run, and to assume that the product density does not change materially during the run. Actually, the product density does vary so that either the quality of the final product or its cost of production may be adversely affected.
It is an object of the invention, accordingly, to provide new and improved mixing apparatus which is capable of continuosly producing a product mix of substantially uniform density.
Another object of the invention is to provide new and improved mixing apparatus of the above character in which the density of the product mix is continuously sensed and gas is introduced into the mix in response to deviation of the sensed density values from a reference value as required to maintain the density substantially constant.